Yazar "Gondal, M. A." seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Öğe
    Cation distribution and Electrical/Dielectric features of Ru substituted CoNiCuZn spinel ferrite nanoparticles
    (Elsevier Ltd, 2025) Almessiere, Munirah A.; Shirsath, S. E.; Baykal, A.; Mihmanlı, Ahmet; Gondal, M. A.; Slimani, Yassine
    In this study, Co0.25Ni0.25Cu0.25Zn0.25RuxFe2-xO4 (Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4) (x ≤ 0.1) nanospinel ferrite (NSFs) were manufactured via sol-gel combustion route, with varying Ru content x ≤ 0.1. The cubic spinel structure was confirmed for all products by XRD analysis. The cubic morphology of the products was confirmed via SEM (Scanning Electron Microscopy), HR-TEM (High Resolution Transmission Electron Microscopy) and TEM (Transmission Electron Microscopy) analyses. The chemical composition of the product has been confirmed by EDX (Energy Dispersive X-ray) analysis. The cation distribution was analyzed using the Bertaut method by comparing observed and calculated intensity ratios of selected X-ray diffraction reflections. The ionic radii of tetrahedral (Td) A-site and octahedral (Oh) B-site cations, theoretical lattice constants, and oxygen positional parameters were determined. Results indicate that Ru substitution leads to a slight expansion in the B-site ionic radius and a subtle increase in the lattice constant, while the A-site configuration remains unaffected. The oxygen positional parameter showed minimal change, indicating structural stability. Additionally, dielectric properties were examined, revealing that the dielectric constant increases with Ru content and T, following MaxwellWagner interfacial polarization. AC conductivity analysis indicated thermally activated hopping mechanisms with enhanced polaron hopping due to Ru substitution. Dielectric measurements showed that the dielectric constant increased with Ru content, reaching a maximum of 150,000 at low frequencies for x = 0.10. AC conductivity analysis demonstrated thermally activated hopping mechanisms, with conductivity values increasing from 0.3 S/m for x = 0.00–1.2 S/m for x = 0.10 at 120 ◦C. This study presents insights into the structural and electrical features of Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4 (x ≤ 0.1) NSFs, which could be valuable for magnetooptical applications.
  • Küçük Resim
    Öğe
    Comprehensive investigation on microstructure, electrical/dielectric and magnetic features of novel equimolar Co3-4x(MnxFexNixCrx)O4 (x = 0.05, 0.10, and 0.15) nanoparticles
    (Elsevier Ltd, 2025) Almessiere, M. A.; Baykal, A.; Slimani, Y.; Shirsath, Sagar E.; Gondal, M. A.; Ali, A.; Mihmanlı, Ahmet
    The main goal of this study is to understand the influence of Mn, Ni, Fe and Cr multi substitution on structural, dielectric, and magnetic properties of Co3O4 nanoparticles (NPs), which have been synthesized via sol-gel synthesis. The results revealed the successfully synthesized multi-substitution spinel oxides through X-ray powder patterns. DXRD are between 14 and 31 nm. AC conductivity exhibited strong temperature (T) and frequency (f) dependence, reflecting mechanisms dominated by interfacial polarization and polaronic conduction. The dielectric constant demonstrated a Maxwell-Wagner type response, influenced by grain boundary polarization and localized charge carriers. Magnetic measurements revealed the coexistence of ferromagnetic (or ferrimagnetic) and antiferromagnetic (or paramagnetic) contributions, with an enhancement in ferromagnetic behaviour attributed to the non-compensated spins, finite size effects, and higher magnetic moments of dopant ions. The coercivity, magnetization, and remanent magnetization were found to increase with the rise in the concentration of Fe, Mn, Ni, and Cr doping ions.